you have in your hands a Debian linux hard drive. You can install in Win/OSx software that allows you to see the drive partitions (lots out there on the internet), or use a Linux machine or Live CD.
FYI… Just about any NAS brand out there, will be some light flavor of a Linux version
If you would like to see if you can recover the whole NAS, search for the debrick/unbrick guides on this forum. There are a couple, pick one.
Or also look into this, if willing to have some other OS on mycloud.
